fix: address Vale linting suggestions

- Capitalize 'API Explorer' per FernStyles.Reject rule
- Define CORS acronym on first use per FernStyles.Acronyms rule

Co-Authored-By: Catherine Deskur <[email protected]>

Author: devin-ai-integration[bot]

fern/products/docs/pages/customization/what-is-docs-yml.mdx

@@ -553,10 +553,10 @@ settings:
 </ParamField>
 
 <ParamField path="settings.disable-explorer-proxy" type="boolean" required={false} default="false" toc={true}>
-  If set to true, the API explorer will bypass the proxy when sending requests directly to your API.
+  If set to true, the API Explorer will bypass the proxy when sending requests directly to your API.
 
   <Warning>
-  When this feature is enabled, your API must have CORS (Cross-Origin Resource Sharing) enabled to allow requests from the documentation domain.
+  When this feature is enabled, your API must have Cross-Origin Resource Sharing (CORS) enabled to allow requests from the documentation domain.
   </Warning>
 </ParamField>